1. A belly-go is when a person's stomach/abdomen protrudes out farther than that of the derriere.
2. A derogatory term used about women who are oddly shaped or obese in or around the stomach/abdomen area. Also see BOOTYDO

Tyrone: Yo son, I don't know what you see in her. Shawty got a crazy belly-go.
Travonte: Stfu, that ain't my girl...She do be making some bangin' cookies though.